A WOMAN in her 30s died and three people were seriously injured when a tourist mini-bus crashed off the Great Ocean Road at Princetown and plunged 20 metres down a gully on Thursday.

The bus was carrying Korean visitors on a trip from Melbourne and smashed through a guard rail and into mature gum trees beside the popular tourist route shortly after 1.30pm.

An Ambulance Victoria spokesman said among those injured was a 16-year-old male passenger who was airlifted to The Alfred hospital with critical head and chest injuries.

The spokesman said another man in his 30s was also flown to The Alfred while other air ambulances took two men in their 40s to Royal Melbourne Hospital.

All four injured men had multiple fractures, the Ambulance Victoria spokesman said.

Victoria Police said the male bus driver and another passenger were airlifted to hospital with serious injuries.

The accident sparked a massive response by emergency services and involved four of the state’s five air ambulances. Helicopters from Warrnambool, Bendigo and Melbourne landed on the Great Ocean Road to rush the injured men to hospital.

Two of the injured men, including the 16-year-old, were trapped in the 12-seater bus for close to an hour before being freed.

Two other passengers, an 18-year-old woman and another woman in her 20s, received minor injuries and were taken to Geelong hospital.

Police said they were called to the accident near the Great Ocean Road’s intersection with The Boulevard about 1.40pm.

The accident happened on a wet road on a sweeping bend, the bus going over a guard rail before plunging down the gully through thick forest and coming to rest on its wheels.

Initial reports suggested the bus was travelling west towards Princetown and crossed the oncoming lane.

Victoria Police’s Major Collision Investigation Group is investigating.

Cobden State Emergency Service volunteer Murray Kelson said the steep and heavily forested terrain made the rescue of those on the bus difficult.

“One passenger had to be cut free and stretchered up the bank,” Mr Kelson said.

Mr Kelson said Port Campbell SES, which is accredited for high rescues, used ropes to bring the person up on a stretcher.

Some of those on the bus were able to get out on their own, he said.

“We are used to that sort of thing in that area. We have done additional training to get people up steep terrain.”

Mr Kelson said the rescue was well co-ordinated.

“There were people everywhere,” he said.

Emergency service vehicles were lined for more than a hundred metres as dozens of volunteers worked together to treat the victims.

The Great Ocean Road was closed to traffic around the crash site between Princetown Road and Gellibrand River Road.

Traffic was detoured via Princetown Road and Lavers Hill-Colac Road.

Nearby resident Tony Duynhoven said the sweeping bend on which the accident happened had been the scene of a number of mishaps.

He said there had been an accident on the bend about six weeks ago, the people in a car suffering minor injuries.

He said the scrub on the roadside in the area had been cut back following the accident.

The sweeping bend on which yesterday’s accident occurred was one of several in that section of the Great Ocean Road, Mr Duynhoven said.

Anyone with any information is urged to contact Crime Stoppers on 1800 333 000 or make a confidential report at www.crimestoppersvic.com.au